Manufacture of lubricating oil



Patented Sept. 11, 1934 UNITED STATES.

MAN UFACTUItE or LUBRICATING on.

Carey Forbes Spencer, Houston, Tex., assignor to Sinclair Refining Company, New York, N. Y., a.

corporation of Maine No Drawing. Application March 9, 1932,

. Serial No. 597,798

3 Claims. (cries-1i This invention relates to improvements in the manufacture of petroleum lubricating oils. More particularly, the invention relates to improvements'in control of the color and bloom of petroleum lubricating oils.

The color, by transmitted light, and the bloom, byreflected light, of petroleum lubricating oils are dependent not only upon the character of the crude petroleum from which the lubricating oil is derived but also upon the processing by which the lubricating oil is derived. The market, however, has tended to associate particular colors and blooms with particular characteristics. This tendency has imposed an added burden on the petroleum refiner in'that it has subjected him to the necessity of controlling operations to produce lubricating oils of particular color and bloom as well as to produce lubricating oils having the required characteristics as lubricants. For example, a distilled-lubricating oil'and a residual lubricating oil having the same general characteristics may be derivedfrom the same crude by different operations, the distilled product may be superior as a lubricant to the residual product, yet the distilled product may have a blue bloom Whereas the residual product may have the green bloom required by the market for this particular product. This invention provides an improved control of the color and bloom of lubricating oils which is independent of the process by which the lubricating oil is produced.

In one aspect, this invention provides a method of imparting the required color and bloom to lubricating oils by means of a dye. In this aspect the invention provides a dye which imparts the required color and bloom to the lubricating oil when used in small proportions and which, within the range of proportions necessary to secure the required color and bloom, does not impair the 9 properties of the petroleum lubricating oil with respect to emulsification or the stability of the oil, either during prolonged storage or during prolonged use, with respect to emulsification properties.

According to the present invention, a residual tar produced by the cracking of petroleum stock at temperatures upwards of 775 F. is diluted with naphtha, this mixture is subjected to treatment with sulphuric acid and the sludge formed as a consequence of this treatment is separated from the mixture, the mixture is then subjected to treatment with an absorbent earth such as fullers earth, the naphtha diluent is then distilled from the mixture, the residuum from this distillation is then subjected to treatment with an absorbent earth, and the residuum is then blended with the petroleum lubricating oil in proportion not exceeding about 3% by volume on the lubricating oil. Percentages approximating 1-1.5% are usually sufficient to impart the required color and bloom to the lubricating oil. The residual tars produced by the cracking of petroleum stocks for the production of gasoline, by pressure distillation for example, are particularly useful in carrying out the invention. Any naphtha character fraction having a boiling range low enough to be readily separatedfromthe residuum produced by distillation may be used. The naphtha diluent should be used in proportion suflicient to promote complete separation from the oilmixture of the sludge produced by the treatment with sulphuric acid. In general, dilution with about -70% by volume on the residual tar of naphtha is sufficient. This will depend, to some extent, upon the degree to which the tar has been concentrated; with more concentrated tars more.- dilution is necessary. With the usual residual tars, theuse-of about 40-60 pounds of 95-100% sulphuric acid per barrel of the residual tar is advantageous, the amount of sulphuric acid per barrel of the diluted mixture will of course be reduced according to the extent of the dilution. The first and second treatments with an absorbent earth may be carried out with about 5-20% of earth by weight on the diluted mixture and on the residuum, respectively, for example.

The invention will be further illustrated by the following specific example of one operation embodying the invention: A mixture consisting of of residual tar having a gravity of 8.5 A. P. I., produced in the pressure distillation of South Texas gas oil at a temperature of 785-810 F. for the production of gasoline, and 40% of naphtha is treated with 30 pounds of 98% sulphuric acid per barrel of mixture at a temperature of 107- 132 F. The sulphuric acid is added in a single dump and agitated, by air blowing, in the conventional agitator, with the mixture until a good separation, or break, of the sludge formed is obtained without the addition of water. The separated sludge is withdrawn, the mixture is permitted to settle for about two hours and any further separated sludge is withdrawn. The mixture is then blown with air for about two hours, to eliminate sulphur dioxide, and again permitted to settle for about two hours and any further separated sludge is withdrawn. The mixture is then contacted with 10% by weight on the mixture of Olmstead earth and the earth filtered from the oil mixture, at a temperature approximat- 'This particular residuum product may have, for

example, a dark green color, a gravity of 10-11 A. P. I., a flash point upwards of about 400 F., and a viscosity upwards of about 950 at 100 F. (Saybolt Universal). It is blended with lubricating oils, including distilled lubricating oils, in proportions up to about 3% by volume on the lubricating oil. The volume of dye produced in carrying out the invention in this manner may approximate, for example, 40% by volume on the residual tar subjected to treatment.

The invention is of special value and application in the manufacture of distilled petroleum lubricating oil. For example, the invention enables the conversion of distilled pale oils having a blue bloom to red oils having a green bloom. The invention is, however, of general application in control of color and bloom of lubricating oils, enabling the petroleum refiner to control the manufacture of lubricating oils toproduce lubricating oils having required characteristics as lubricants and independently to control this manufacture to produce lubricating oils having required color and bloom.

I claim:

1. In the manufacture of petroleum lubricating oils, the improvement which comprises diluting with naphtha a residual tar produced by the cracking of a petroleum stock at temperatures upwards of 775 F., subjecting the mixture to an absorbent earth, distilling the naphtha diluent from the mixture and subjecting the residuum to treatment with an absorbent earth, and thereafter blending the residuum with a lubricating oil in proportion not exceeding about 3% by volume on the lubricating oil, thereby imparting a green bloom to the lubricating oil.

2. In the manufacture of distilled petroleum lubricating oils, the improvement which comprises diluting with naphtha a residual tar produced by the cracking of, a petroleum stock at temperatures upwards of 775 F., subjecting the mixture to treatment with sulphuric acid and thereafter separating the sludge formed, subjecting the mixture after sludge separation to treatment with an absorbent earth, distilling the naphtha diluent from the mixture and subjecting the residuum to treatment with an absorbent earth, and thereafter blending the residuum with a distilled lubricating oil in proportion not exceeding about 3% by volume on the lubricating oil, thereby imparting a green bloom to the lubricating oil.

3. In the manufacture of petroleum lubricating oils, the improvement which comprises diluting with naphtha a residual tar produced by the cracking of a petroleum stock at temperatures upwards of 775 F., subjecting the mixture to treatment with about 40-60 pounds of -100% sulphuric acid per barrel of the residual tar and thereafter, separating the sludge formed, subjecting the mixture after sludge separation to treatment with about 5-20% by weight on the mixture of an absorbent earth, distilling the naphtha diluent from the mixture and subjecting the residuum to treatment with about 5-20% by weight on the residuum of an absorbent earth, and thereafter blending the residuum with a lubricating oil in proportion not exceeding about 3% by volume on the lubricating oil, thereby imparting a green bloom to the lubricating oil.

CAREY FORBES SPENCER. 

